Wife is Expecting

Here is an old joke my Dad told me many years ago:

There was a young private in the army, and on Friday he went to ask his
Sarge for a weekend pass, to go visit his wife. He said, "She's expecting",
so the sergeant gave him leave.

The following weekend, the Private again says, "Sarge, can I have a weekend
pass? My wife's expecting." Sarge again says okay.

And again the following weekend, same story again.

Finally, after a month of weekend leaves, when the young private again
approaches his sergeant for a weekend leave, and Sarge asks why...

Of course: "She's expecting". Sarge has had too much and blows up, "WHAT is
your wife expecting exactly?!"

Private: "Well, ME, of course."